BooksecrCollected Volumepp. vii–viiiIntroductionCarel FaberRoyal Institute of Technology, Stockholm, SwedenMathSciNetzbMATH OpenGerard van der GeerUniversity of AmsterdamMathSciNetzbMATH OpenEduard LooijengaTsinghua University, Beijing, Haidan District, ChinaMathSciNetzbMATH OpenDownload Chapter PDF